I am sure there are people in this world who would attempt to make such fakes, but I am equally sure that they could not fool experts. While it is true you cannot carbon date stone, you can't accurately fake patina nor a chain of custody in an archaeological dig. Everything is done with meticulous record keeping and with numerous people observing, just putting a few rocks in your pocket and sprinkling them about wouldn't fool anyone. These artifacts are real or they never would have passed muster of a serious examination by trained experts.